Obesity is major health problem in the United States, that is associated with coronary heart disease (CHD), hypertension, diabetes, and cancer. Efforts to answer important questions about obesity, such as whether modifications in body weight over the long term will reduce CHD incidence or risk factors and what individual difference variables determine who will benefit from weight reduction, have been hampered by the inability to produce reliable long-term weight loss in outpatient populations. The goal of the proposed research is to develop intervention methods that would be capable of producing larger, sustained weight losses in outpatient populations. Two intervention strategies will be investigated: the use of incentives and food provision. These strategies are derived from social learning theory and are intended to directly change the environmental antecedents and consequences controlling eating behavior. In the proposed study, one hundred obese subjects (50 male, 50 female) will be recruited at each of two centers (University of Pittsburgh and University of Minnesota). These subjects will be randomly assigned to one of five treatment groups: no treatment control, standard behavioral nutrition program, standard program with incentives, standard program with food provision, and standard program with both incentives and food provision. The effectiveness of the treatments will be analyzed by assessing changes in body weight, CHD risk factors (lipids, blood pressure, insulin and glucose) and proces variables (eating and exercise behavior, knowledge, barriers to adherence) at 6 month intervals for 18 months. The study hopes to accomplish three objectives: 1) to develop treatment methods that will produce greater and better maintained weight losses, 2) to determine the specific behaviors most responsible for successful weight loss, and 3) to assess the relationship between weight loss and change in CHD risk factors among individuals who differ in weight loss history, body fat distribution, and insulin levels.